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Tobacco Control Apr 2024Studies of Electronic Nicotine Delivery Systems (ENDS) toxicity have largely focused on individual components such as flavour additives, base e-liquid ingredients...
Studies of Electronic Nicotine Delivery Systems (ENDS) toxicity have largely focused on individual components such as flavour additives, base e-liquid ingredients (propylene glycol, glycerol), device characteristics (eg, model, components, wattage), use behaviour, etc. However, vaping involves inhalation of chemical mixtures and interactions between compounds can occur that can lead to different toxicities than toxicity of the individual components. Methods based on the additive toxicity of individual chemical components to estimate the health risks of complex mixtures can result in the overestimation or underestimation of exposure risks, since interactions between components are under-investigated. In the case of ENDS, the potential of elevated toxicity resulting from chemical reactions and interactions is enhanced due to high operating temperatures and the metallic surface of the heating element. With the recent availability of a wide range of e-liquid constituents and popularity of do-it-yourself creation of e-liquid mixtures, the need to understand chemical and physiological impacts of chemical combinations in ENDS e-liquids and aerosols is immediate. There is a significant current knowledge gap concerning how specific combinations of ENDS chemical ingredients result in synergistic or antagonistic interactions. This commentary aims to review the current understanding of chemical reactions between e-liquid components, interactions between additives, chemical reactions that occur during vaping and aerosol properties and biomolecular interactions, all of which may impact physiological health.
PubMed: 38658055
DOI: 10.1136/tc-2023-058546 -
The Journal of Emergency Medicine Nov 2023Antifreeze poisoning is potentially life-threatening and often requires multiple antidotal therapies and hemodialysis. Ethylene or propylene glycol toxicity is commonly...
BACKGROUND
Antifreeze poisoning is potentially life-threatening and often requires multiple antidotal therapies and hemodialysis. Ethylene or propylene glycol toxicity is commonly caused by antifreeze ingestion. However, ingestion of antifreeze is typically not associated with methemoglobinemia. Currently, only one other case of antifreeze ingestion causing combined ethylene glycol poisoning and methemoglobinemia has been reported.
CASE REPORT
A 56-year-old man presented after a witnessed, intentional, large-volume antifreeze ingestion. Evaluation revealed dark brown blood and significantly elevated methemoglobin and ethylene glycol levels. He was successfully treated with methylene blue, fomepizole, and hemodialysis. No other potential cause for methemoglobinemia was elucidated, and further research indicated that minor components of the specific antifreeze product served as an oxidizing agent. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case highlights the impact of minor, unreported product components that may significantly contribute to clinical toxicity, as well as the need to remain vigilant when reviewing product information and potential limitations therein.
PubMed: 37734990
DOI: 10.1016/j.jemermed.2023.06.006 -
Biomacromolecules Oct 2023In this work, isocyanate-free formulations for poly(propylene glycol) polyurethane elastomers are studied. These formulations are based on poly(propylene glycol)...
In this work, isocyanate-free formulations for poly(propylene glycol) polyurethane elastomers are studied. These formulations are based on poly(propylene glycol) end-capped by CO-sourced cyclic carbonate (bisCC PPG) macromonomers able to react with amines leading to poly(hydroxyurethane)s. In order to obtain covalent networks, two curing approaches are studied. First, the direct thermally activated cross-linking of bisCC PPG with a mixture of various aliphatic or aromatic diamines and a triamine is investigated, and in particular the nature of the diamine on the mechanical properties. In the second approach, UV-activated formulations are developed by reacting bisCC PPG with allylamine followed by the addition of a trithiol by photoactivated thiol-ene reaction. The swelling tests show that both systems provide highly cross-linked polymer networks and complementary characterizations highlighted excellent mechanical properties. Thanks to the fast curing and adapted viscosity of the developed photoactive formulation, the latter was found suitable for use as a photoresin for 3D printing as demonstrated by printing a vaginal ring by a nozzle-based photoprinter.
Topics: Elastomers; Propylene Glycol; Polymers; Polyurethanes; Isocyanates
PubMed: 36113039
DOI: 10.1021/acs.biomac.2c00860 -
Biomedicine & Pharmacotherapy =... Oct 2023Neurogenesis is a process of generating neural stem cells (NSCs) as functional neurons can be decreased after chemotherapy treatments. Methotrexate (MTX) is a folate...
Neurogenesis is a process of generating neural stem cells (NSCs) as functional neurons can be decreased after chemotherapy treatments. Methotrexate (MTX) is a folate antagonist that is used for cancer treatment but has negative effects, including oxidative stress, neuronal apoptosis and cognitive impairments. Hesperidin (Hsd), a flavonoid found in citrus fruits, has antioxidant and neuroprotection properties. This study investigated whether Hsd could attenuate impairments of hippocampal neural stem cells related to apoptosis induced by MTX. Spraque-Dawley rats (n = 24) were divided into 4 groups: (1) Vehicle group received propylene glycol (21 days) and 0.9% normal saline (day 8 and 15), (2) Hsd group received 100 mg/kg (21 days), (3) MTX group received 75 mg/kg (days 8 and 15) and (4) MTX+Hsd group received MTX, 75 mg/kg (day 8 and 15) and Hsd 100 mg/kg (21 days). Our results showed that MTX decreased hippocampal neural stem cells including SRY (sex determining region Y)-box 2 (SOX2) and nestin. MTX diminished vascular related (VR) Ki-67 positive cells in the hippocampus but not non-vascular related (NVR) Ki-67. Additionally, MTX reduced SOX2, nestin, postsynaptic density protein 95 (PSD-95) and B-cell lymphoma-2 family of proteins (Bcl-2), whereas Bax and caspase-3 were enhanced in the hippocampal tissues. Interestingly, co-treatment with Hsd and MTX revealed upregulation of SOX2, nestin and VR Ki-67 positive cells as well as elevated SOX2, nestin, PSD-95 and Bcl-2 proteins. Moreover, receiving both Hsd and MTX significantly suppressed increased Bax and caspase-3. These results confirm that Hsd can ameliorate MTX-induced impairments of hippocampal NSC proliferation and neuronal apoptosis.
Topics: Animals; Rats; Hesperidin; Methotrexate; Caspase 3; Nestin; Ki-67 Antigen; bcl-2-Associated X Protein; Apoptosis; Neural Stem Cells; Disks Large Homolog 4 Protein; Hippocampus
PubMed: 37597319
DOI: 10.1016/j.biopha.2023.115329 -
American Journal of Physiology. Lung... Nov 2023The prevalence of electronic cigarette (EC) use among adult with asthma has continued to increase over time, in part due to the belief of being less harmful than...
The prevalence of electronic cigarette (EC) use among adult with asthma has continued to increase over time, in part due to the belief of being less harmful than smoking. However, the extent of their toxicity and the involved mechanisms contributing to the deleterious impact of EC exposure on patients with preexisting asthma have not been delineated. In the present project, we tested the hypothesis that EC use contributes to respiratory damage and worsening inflammation in the lungs of patients with asthma. To define the consequences of EC exposure in established asthma, we used a mouse model with/without preexisting asthma for short-term exposure to EC aerosols. C57/BL6J mice were sensitized and challenged with a DRA (dust mite, ragweed, , 200 µg/mL) mixture and exposed daily to EC with nicotine (2% nicotine in 30:70 propylene glycol: vegetable glycerin) or filtered air for 2 wk. The mice were evaluated at 24 h after the final EC exposure. After EC exposure in asthmatic mice, lung inflammatory cell infiltration and goblet cell hyperplasia were increased, whereas EC alone did not cause airway inflammation. Our data also show that mitochondrial DNA (mtDNA) content and a key mtDNA regulator, mitochondrial transcription factor A (TFAM), are reduced in asthmatic EC-exposed mice in a sex-dependent manner. Together, these results indicate that TFAM loss in lung epithelium following EC contributes to male-predominant sex pathological differences, including mitochondrial damage, inflammation, and remodeling in asthmatic airways. Respiratory immunity is dysregulated in preexisting asthma, and further perturbations by EC use could exacerbate asthma severity. However, the extent of their toxicity and the involved mechanisms contributing to the deleterious impact of EC exposure on patients with preexisting asthma have not been delineated. We found that EC has unique biological impacts in lungs and potential sex differences with loss of TFAM, a key mtDNA regulator, in lung epithelial region from our animal EC study.
Topics: Humans; Adult; Male; Female; Mice; Animals; Electronic Nicotine Delivery Systems; Nicotine; Respiratory Aerosols and Droplets; Asthma; Lung; Pneumonia; Inflammation; Disease Models, Animal; DNA, Mitochondrial
PubMed: 37697923
DOI: 10.1152/ajplung.00033.2023 -
Journal of Applied Microbiology Apr 2024In the 1940s and 1950s, researchers seeking safe and novel ways to eliminate airborne pathogens from enclosed spaces, investigated glycol vapours as a method of...
In the 1940s and 1950s, researchers seeking safe and novel ways to eliminate airborne pathogens from enclosed spaces, investigated glycol vapours as a method of disinfection. More recently, the COVID-19 pandemic highlighted the need for a non-toxic aerial disinfectant that can be used in the presence of people. This scoping review is intended to analyse the early and more recent literature on glycol disinfection, scrutinizing the methodologies used, and to determine if the use of glycols as modern-day disinfectants is justified PRISMA-ScR guidelines were used to assess the 749 articles retrieved from the Web of Science platform, with 46 articles retained after the search strategy was applied. Early studies generally demonstrated good disinfection capabilities against airborne bacteria and viruses, particularly with propylene glycol (PG) vapour. Vapour pressure, relative humidity, and glycol concentration were found to be important factors affecting the efficacy of glycol vapours. Contact times depended mainly on the glycol application method (i.e. aerosolization or liquid formulation), although information on how glycol efficacy is impacted by contact time is limited. Triethylene glycol (TEG) is deemed to have low toxicity, carcinogenicity, and mutagenicity and is registered for use in air sanitization and deodorization by the US Environmental Protection Agency. Glycols are also used in liquid formulations for their antimicrobial activity against a wide range of microorganisms, although when used as a non-active excipient in products, their contribution to antimicrobial efficacy is rarely assessed. The appropriate use of liquid glycol-containing formulations was found to positively impact the antimicrobial capabilities of disinfectants when used at temperatures <0, food preservatives, and dental medicaments. Providing modern delivery technology can accurately control environmental conditions, the use of aerosolized glycol formulations should lead to successful disinfection, aiding infection prevention, and control regimens.
Topics: Humans; Pandemics; Disinfectants; Disinfection; Anti-Infective Agents; Propylene Glycol; Gases
PubMed: 38573833
DOI: 10.1093/jambio/lxae071 -
Diagnostics (Basel, Switzerland) Oct 2023(1) Background: The use of electronic cigarettes has become widespread in recent years. The use of e-cigarettes leads to milder pathological conditions compared to...
(1) Background: The use of electronic cigarettes has become widespread in recent years. The use of e-cigarettes leads to milder pathological conditions compared to traditional cigarette smoking. Nevertheless, e-liquid vaping can cause morphological changes in lung tissue, which affects and impairs gas exchange. This work studied the changes in morphological and optical properties of lung tissue under the action of an e-liquid aerosol. To do this, we implemented the "passive smoking" model and created the specified concentration of aerosol of the glycerol/propylene glycol mixture in the chamber with the animal. (2) Methods: In ex vivo studies, the lungs of Wistar rats are placed in the e-liquid for 1 h. For in vivo studies, Wistar rats were exposed to the e-liquid vapor in an aerosol administration chamber. After that, lung tissue samples were examined ex vivo using optical coherence tomography (OCT) and spectrometry with an integrating sphere. Absorption and reduced scattering coefficients were estimated for the control and experimental groups. Histological sections were made according to the standard protocol, followed by hematoxylin and eosin staining. (3) Results: Exposure to e-liquid in ex vivo and aerosol in in vivo studies was found to result in the optical clearing of lung tissue. Histological examination of the lung samples showed areas of emphysematous expansion of the alveoli, thickening of the alveolar septa, and the phenomenon of plasma permeation, which is less pronounced in in vivo studies than for the exposure of e-liquid ex vivo. E-liquid aerosol application allows for an increased resolution and improved imaging of lung tissues using OCT. Spectral studies showed significant differences between the control group and the ex vivo group in the spectral range of water absorption. It can be associated with dehydration of lung tissue owing to the hyperosmotic properties of glycerol and propylene glycol, which are the main components of e-liquids. (4) Conclusions: A decrease in the volume of air in lung tissue and higher packing of its structure under e-liquid vaping causes a better contrast of OCT images compared to intact lung tissue.
PubMed: 37958237
DOI: 10.3390/diagnostics13213340 -
Atherosclerosis May 2024Metabolic associated fatty liver disease (MAFLD) is a novel concept proposed in 2020, which is more practical for identifying patients with fatty liver disease with high...
BACKGROUND
Metabolic associated fatty liver disease (MAFLD) is a novel concept proposed in 2020, which is more practical for identifying patients with fatty liver disease with high risk of disease progression. Fatty liver is a driver for extrahepatic complications, particularly cardiovascular diseases (CVD). Although the risk of CVD in MAFLD could be predicted by carotid ultrasound test, a very early stage prediction method before the formation of pathological damage is still lacking.
METHODS
Stool microbiomes and plasma metabolites were compared across 196 well-characterized participants encompassing normal controls, simple MAFLD patients, MAFLD patients with carotid artery pathological changes, and MAFLD patients with diagnosed coronary artery disease (CAD). 16S rDNA sequencing data and untargeted metabolomic profiles were interrogatively analyzed using differential abundance analysis and random forest (RF) machine learning algorithm to identify discriminatory gut microbiomes and metabolomic.
RESULTS
Characteristic microbial changes in MAFLD patients with CVD risk were represented by the increase of Clostridia and Firmicutes-to-Bacteroidetes ratios. Faecalibacterium was negatively correlated with mean-intima-media thickness (IMT), TC, and TG. Megamonas, Bacteroides, Parabacteroides, and Escherichia were positively correlated with the exacerbation of pathological indexes. MAFLD patients with CVD risk were characterized by the decrease of lithocholic acid taurine conjugate, and the increase of ethylvanillin propylene glycol acetal, both of which had close relationship with Ruminococcus and Gemmiger. Biotin l-sulfoxide had positive correlation with mean-IMT, TG, and weight. The general auxin pesticide beta-naphthoxyacetic acid and the food additive glucosyl steviol were both positively correlated with the increase of mean-IMT. The model combining the metabolite signatures with 9 clinical parameters accurately distinguished MAFLD with CVD risk in the proband and validation cohort. It was found that citral was the most important discriminative metabolite marker, which was validated by both in vitro and in vivo experiments.
CONCLUSIONS
Simple MAFLD patients and MAFLD patients with CVD risk had divergent gut microbes and plasma metabolites. The predictive model based on metabolites and 9 clinical parameters could effectively discriminate MAFLD patients with CVD risk at a very early stage.
Topics: Humans; Gastrointestinal Microbiome; Male; Female; Middle Aged; Feces; Metabolomics; Cardiovascular Diseases; Biomarkers; Risk Assessment; Case-Control Studies; Aged; Predictive Value of Tests; Bacteria; Heart Disease Risk Factors; Adult; Non-alcoholic Fatty Liver Disease; Machine Learning; Carotid Intima-Media Thickness
PubMed: 38581738
DOI: 10.1016/j.atherosclerosis.2024.117526 -
Contact Dermatitis Aug 2023Propylene glycol (PG) is used in a variety of cosmetics, food and pharmaceuticals. PG is a known sensitizer but also irritating when patch tested (PT).
BACKGROUND
Propylene glycol (PG) is used in a variety of cosmetics, food and pharmaceuticals. PG is a known sensitizer but also irritating when patch tested (PT).
OBJECTIVES
The aims were to investigate the frequency of contact sensitization to PG and to identify cases of allergic contact dermatitis (ACD).
METHODS
A retrospective study was performed on patients PT at the Skin Health Institute (SHI), Victoria, Australia to PG 5% pet. and PG 10% aq. between 1 January 2005 and 31 December 2020.
RESULTS
In all, 6761 patients were PT to PG and 21 (0.31%) reacted. Of those 21 individuals, 9 (42.9%) had a relevant reaction. 75% of relevant positive reactions were in patients PT to PG 10% aq. The most common source of PG exposure was topical medicaments (77.8% of relevant reactions) and moisturizers, with the largest group being topical corticosteroids.
CONCLUSION
Contact sensitization to PG in the patch test population remains uncommon, although it is possible that testing with concentrations of 5%-10% PG did not identify all reactions. Topical corticosteroids were the most important cause. Patients with suspected contact dermatitis to topical corticosteroids should be PT to PG.
Topics: Humans; Dermatitis, Allergic Contact; Retrospective Studies; Propylene Glycol; Allergens; Patch Tests; Dermatologic Agents; Victoria; Glucocorticoids
PubMed: 37100088
DOI: 10.1111/cod.14325 -
Toxics Dec 2023Toxicological evaluations of flavor chemicals for use in inhalation products that utilize heat for aerosol generation are complicated because of the potential effect...
Toxicological evaluations of flavor chemicals for use in inhalation products that utilize heat for aerosol generation are complicated because of the potential effect heat may have on the flavor chemical. The objective was to develop a thermal degradation technique to screen flavor chemicals as part of a toxicological testing program for their potential use in ENDS formulations. Based upon published data for acetaldehyde, acrolein, and glycidol from ENDS products (common thermal degradants of propylene glycol and glycerin), the pyrolizer temperature was adjusted until a similar ratio of acetaldehyde, acrolein, and glycidol was obtained from a 60/40 ratio (/) of glycerin/propylene glycol via GC/MS analysis. For each of 90 flavor chemicals, quantitative measurements of acetaldehyde, acrolein, and glycidol, in addition to semiquantitative non-targeted analysis tentatively identifying chemicals from thermal degradation, were obtained. Twenty flavor chemicals transferred at greater than 99% intact, another 26 transferred at greater than 95% intact, and another 15 flavor chemicals transferred at greater than 90% intact. Most flavor chemicals resulted in fewer than 10-12 tentatively identified thermal degradants. The practical approach to the thermal degradation of flavor chemicals provided useful information as part of the toxicological evaluation of flavor chemicals for potential use in ENDS formulations.
PubMed: 38250972
DOI: 10.3390/toxics12010016